$$
      \downharpoonleft,
      \downharpoonright,
      \leftharpoondown,
      \leftharpoonup,
      \leftrightharpoons,
      \rightharpoondown,
      \rightharpoonup,
      \rightleftharpoons,
      \rightleftharpoons,
      \upharpoonleft,
      \upharpoonright
$$
